In recent years, the new science of Genetic Genealogy has been developed which applies DNA analysis to Genealogy. It uses three types of DNA from a human cell. These are the following:
- mDNA - Mitochondrial DNA, passed only from the mother to daughter/son, mutates less than the others and useful for ancient lines.
- yDNA - Y-Chromosome DNA, only in males and passed from the father. Mutates quickly and useful for ancient lines.
- aDNA - Autosomal DNA, everything but the sex-chromosomes (X and Y), useful for cousin matches. The X-chromosome is of limited use.
yDNA measures the changes between parts of the Y-chromosome and how it affects people's descendants. The Y-chromosome is unique to the male line, as are surnames.
There are two kinds of analysis called STR and SNP.
STR was the first developed and the less accurate. The changes occur very often which leads to a lot of uncertainty. An early STR analysis from 2006 is shown in the graphic here.
SNP was developed later and is much more definite. The changes seldom occur and are very rarely repeated. This is not useful for finding cousins (as of now) but is very useful in tracking the movements of peoples and tribes going back hundreds or thousands of years.
The first work that was important for Irish Genetic Genealogy was done in 2005/2006 by Brian McEvoy of Trinity College Dublin. He used STR data from a sample of a few hundred surnames drawn from the phonebook throughout Ireland. Among the names were Haughey and Dunleavy. Haughey can be a phonetic rendition of Ó hEochaidh. The 1659 spelling of O'Hoy in Pendar's work was from an English viewpoint. In Ireland, Hoy is now Hoey and pronounced closer to Haughey. The last five kings of the Dál Fiatach were brothers who changed their surname from Hoey to MacDunleavy after Dunleavy Ó hEochaidh who was a king who died in 1091. After the Normans drove the Dál Fiatach out of County Down, the MacDunleavy were known to have become the hereditary physicians to the Cenél Chonaill in southwest Tir Chonaill (Donegal) near their base in Donegal Town.
From Griffith's Valuation from 1856 in Donegal, we find the almost all Haughey clustered in far southwest Donegal near Glencolumbkille and the MacDunleavy in the same area. The graphic above is taken from McEvoy's work for the Haighey/MacDunleavy and compares a living Hoy at the top with McEvoy's results. He identified several markers called haplotypes among the STR data. Among them were R1b, M222 (subgroup of the former), and 'I' which is likely pre-Bell-Beaker and associated with a subgroup of the Uladh and the Maginness and McCartan lines in west County Down. We can see the closeness of the living Hoy with the M222 men.
This link will show the Hoy family connections to these Donegal men.
